8 ms·

I was wondering how this UUV was powered and all that DARPA was willing to divulge was "Novel energy management techniques" and "undersea energy harvesting" [1]

by erikig 2y ago

I was wondering how this UUV was powered and all that DARPA was willing to divulge was "Novel energy management techniques" and "undersea energy harvesting" [1]. Anyone have any insights? [1] https://www.darpa.mil/news-events/2024-05-01 https://www.darpa.mil/news-events/2024-05-01

causal 2y ago
I saw an Instagram Reel where someone claimed it could loiter on the seabed for extended periods powered by geothermal, but that sounds pretty fanciful to me.
- runjake 2y ago
  This is an inaccurate take. It loiters on the bottom in an energy-efficient sleep mode. Separately, it collects small amounts of energy via geothermal means similar to something like regenerative braking. This, of course, allows it to sleep for longer periods.
  - causal 2y ago
    That definitely makes more sense but where did you learn this?
    - runjake 2y ago
      From both a defense publication article, written by the Program Manager, Kyle Woerner, and reading up on the company purportedly behind the geothermal research. They go into a bit more detail. If I can find online links, I’ll post a follow up comment with them.
    - petesergeant 2y ago
      WarThunder forums[0] 0: https://www.eurogamer.net/war-thunder-players-leak-military-documents-on-forums-again https://www.eurogamer.net/war-thunder-players-leak-military-...
zardo 2y ago
https://www.whoi.edu/oceanus/feature/green-energy-powers-undersea-glider/ https://www.whoi.edu/oceanus/feature/green-energy-powers-und...
2rsf 2y ago
The article mentions Seatrec that have more information: https://seatrec.com/technology/ https://seatrec.com/technology/
- conradev 2y ago
  It’s an underwater heat pump!
  - ttul 2y ago
    I remember reading about this concept in a kids book about “the future” published by Usborne in the mid-1980s.
  - tomphoolery 2y ago
    someone at Northrop Grumman has been watching Technology Connections...
great_psy 2y ago
Does not ‘seem’ like the right shape for it, but could it use ocean currents ? Similar idea to those weather balloons we were talking about last year ? Is that even possible in the ocean ?
- JKCalhoun 2y ago
  There are definitely underwater gliders: https://en.wikipedia.org/wiki/Underwater_glider https://en.wikipedia.org/wiki/Underwater_glider
jauntywundrkind 2y ago
It's afaik the only glider type UUV (ed: being looked at by .mil. and production intended. and bigger than the research gliders by far.), afaik. Which is super interesting in itself, for endurance purposes. But perhaps this depth-changing mission profile is also key to its energy harvesting? Just guessing here, but... it's sinking and rising. Well, perhaps it can take some mass of water onboard & run temperature differential energy harvesting off that. Take on warm surface water, slowly glide down 1000 ft (while going much further forward), then run a thermo-electric generator against the cold deep. Swap water & take 300 gallons of cold water, glide up 1000 ft (and forward), then run a thermoelectric generator against the warmer surface water or the air and/or solar. Repeat ad-infinitum. No idea what kind of power you could pull here but maybe, and it fits with the glider core concept. And yeah, maybe if you do find an underwater vent you can supercharge? :) Shout out to The War Zone (TWZ)'s coverage over time. The recent is decent but links their previous which looked about some. https://www.twz.com/news-features/manta-ray-underwater-drone-even-more-enormous-than-we-thought https://www.twz.com/news-features/manta-ray-underwater-drone... TWZ talk about something mentioned elsewhere in the comments, yes, the data-linking challenges are partly tackled by having a "data bubble" that can float to the surface & uplink, who knows, maybe downlink relay too (unspecified). I definitely want to imagine the data bubble as a recursive system, as itself a smaller glider drone, but I'm 100% making that up, is my sci-fi impulse.
- JKCalhoun 2y ago
  Is this not a glider? https://en.wikipedia.org/wiki/Underwater_glider https://en.wikipedia.org/wiki/Underwater_glider
- rjeli 2y ago
  You can do it without a TEG: https://sci-hub.se/10.1109/48.972077 https://sci-hub.se/10.1109/48.972077 Essentially you use a fluid which freezes at the bottom of the ocean and loses volume (some kind of paraffin) And then you hook it up with some actuated valves and N2 accumulators so the volume change and energy harvesting happens "out of phase" - at the surface, you can deflate an external bladder and sink, and at the bottom, you use some stored energy to reinflate the bladder With a large enough volume you get near infinite range, only have to pay for payload and any onboard electronics this report has some more info on the absurd efficiency of thermal gliders: https://escholarship.org/content/qt1c28t6bb/qt1c28t6bb_noSplash_8f45135a2fb9e138dd6d6048ba34fba6.pdf https://escholarship.org/content/qt1c28t6bb/qt1c28t6bb_noSpl...
wolverine876 2y ago
This article covers it in more detail: https://www.defenseone.com/technology/2024/05/giant-military-manta-ray-drone-passes-first-ocean-test/396244/ https://www.defenseone.com/technology/2024/05/giant-military... “One thing that you notice in underwater vehicle design is you typically can have either a vehicle that lasts very long periods of time but can't really carry anything with it,” Woerner said on a podcast in 2022. “But if you want something that can carry a sensor or payload that is perhaps a larger size or mass, or has a larger energy draw, you tend to need a more traditional underwater vehicle, propeller driven in most cases. And those tend to not have anywhere near the endurance” that the military is looking for. The ocean itself is full of potential sources of energy, such as currents, waves, and even subtle differences in water temperature or salt levels. But there’s no single perfect source of ocean energy for what DARPA is trying to accomplish. “If you're interested in maybe closer to surface transport, wave energy is a really great resource, most of the wave energy is distributed near the surface. If you want to go into deeper water, right? That means that wave energy wouldn't be a great resource for that,” Sandia National Laboratory engineer Kelley Ruehl, an advisor on the program, said on the podcast. Similarly, current energy is a very localized resource, where we have tidal streets— those are unique locations in the world. So it's a very specific place that one would need to harvest tidal-energy resource.” DARPA said PacMar Technologies, another contractor on the Manta Ray program, will spend the rest of this year testing a full-scale energy-harvesting system.
- moffkalast 2y ago
  So... it's a glider? The top fin does make it very likely.

by erikig 2y ago

causal 2y ago

I saw an Instagram Reel where someone claimed it could loiter on the seabed for extended periods powered by geothermal, but that sounds pretty fanciful to me.

runjake 2y ago
This is an inaccurate take. It loiters on the bottom in an energy-efficient sleep mode. Separately, it collects small amounts of energy via geothermal means similar to something like regenerative braking. This, of course, allows it to sleep for longer periods.
- causal 2y ago
  That definitely makes more sense but where did you learn this?
  - runjake 2y ago
    From both a defense publication article, written by the Program Manager, Kyle Woerner, and reading up on the company purportedly behind the geothermal research. They go into a bit more detail. If I can find online links, I’ll post a follow up comment with them.
  - petesergeant 2y ago
    WarThunder forums[0] 0: https://www.eurogamer.net/war-thunder-players-leak-military-documents-on-forums-again https://www.eurogamer.net/war-thunder-players-leak-military-...

zardo 2y ago

https://www.whoi.edu/oceanus/feature/green-energy-powers-undersea-glider/ https://www.whoi.edu/oceanus/feature/green-energy-powers-und...

2rsf 2y ago

The article mentions Seatrec that have more information: https://seatrec.com/technology/ https://seatrec.com/technology/

conradev 2y ago
It’s an underwater heat pump!
- ttul 2y ago
  I remember reading about this concept in a kids book about “the future” published by Usborne in the mid-1980s.
- tomphoolery 2y ago
  someone at Northrop Grumman has been watching Technology Connections...

great_psy 2y ago

Does not ‘seem’ like the right shape for it, but could it use ocean currents ? Similar idea to those weather balloons we were talking about last year ? Is that even possible in the ocean ?

JKCalhoun 2y ago
There are definitely underwater gliders: https://en.wikipedia.org/wiki/Underwater_glider https://en.wikipedia.org/wiki/Underwater_glider

jauntywundrkind 2y ago

It's afaik the only glider type UUV (ed: being looked at by .mil. and production intended. and bigger than the research gliders by far.), afaik. Which is super interesting in itself, for endurance purposes. But perhaps this depth-changing mission profile is also key to its energy harvesting? Just guessing here, but... it's sinking and rising. Well, perhaps it can take some mass of water onboard & run temperature differential energy harvesting off that. Take on warm surface water, slowly glide down 1000 ft (while going much further forward), then run a thermo-electric generator against the cold deep. Swap water & take 300 gallons of cold water, glide up 1000 ft (and forward), then run a thermoelectric generator against the warmer surface water or the air and/or solar. Repeat ad-infinitum. No idea what kind of power you could pull here but maybe, and it fits with the glider core concept. And yeah, maybe if you do find an underwater vent you can supercharge? :) Shout out to The War Zone (TWZ)'s coverage over time. The recent is decent but links their previous which looked about some. https://www.twz.com/news-features/manta-ray-underwater-drone-even-more-enormous-than-we-thought https://www.twz.com/news-features/manta-ray-underwater-drone... TWZ talk about something mentioned elsewhere in the comments, yes, the data-linking challenges are partly tackled by having a "data bubble" that can float to the surface & uplink, who knows, maybe downlink relay too (unspecified). I definitely want to imagine the data bubble as a recursive system, as itself a smaller glider drone, but I'm 100% making that up, is my sci-fi impulse.

JKCalhoun 2y ago
Is this not a glider? https://en.wikipedia.org/wiki/Underwater_glider https://en.wikipedia.org/wiki/Underwater_glider
rjeli 2y ago
You can do it without a TEG: https://sci-hub.se/10.1109/48.972077 https://sci-hub.se/10.1109/48.972077 Essentially you use a fluid which freezes at the bottom of the ocean and loses volume (some kind of paraffin) And then you hook it up with some actuated valves and N2 accumulators so the volume change and energy harvesting happens "out of phase" - at the surface, you can deflate an external bladder and sink, and at the bottom, you use some stored energy to reinflate the bladder With a large enough volume you get near infinite range, only have to pay for payload and any onboard electronics this report has some more info on the absurd efficiency of thermal gliders: https://escholarship.org/content/qt1c28t6bb/qt1c28t6bb_noSplash_8f45135a2fb9e138dd6d6048ba34fba6.pdf https://escholarship.org/content/qt1c28t6bb/qt1c28t6bb_noSpl...

wolverine876 2y ago

This article covers it in more detail: https://www.defenseone.com/technology/2024/05/giant-military-manta-ray-drone-passes-first-ocean-test/396244/ https://www.defenseone.com/technology/2024/05/giant-military... “One thing that you notice in underwater vehicle design is you typically can have either a vehicle that lasts very long periods of time but can't really carry anything with it,” Woerner said on a podcast in 2022. “But if you want something that can carry a sensor or payload that is perhaps a larger size or mass, or has a larger energy draw, you tend to need a more traditional underwater vehicle, propeller driven in most cases. And those tend to not have anywhere near the endurance” that the military is looking for. The ocean itself is full of potential sources of energy, such as currents, waves, and even subtle differences in water temperature or salt levels. But there’s no single perfect source of ocean energy for what DARPA is trying to accomplish. “If you're interested in maybe closer to surface transport, wave energy is a really great resource, most of the wave energy is distributed near the surface. If you want to go into deeper water, right? That means that wave energy wouldn't be a great resource for that,” Sandia National Laboratory engineer Kelley Ruehl, an advisor on the program, said on the podcast. Similarly, current energy is a very localized resource, where we have tidal streets— those are unique locations in the world. So it's a very specific place that one would need to harvest tidal-energy resource.” DARPA said PacMar Technologies, another contractor on the Manta Ray program, will spend the rest of this year testing a full-scale energy-harvesting system.

moffkalast 2y ago
So... it's a glider? The top fin does make it very likely.